Submitted to: Pesticide Biochemistry and Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/9/2004
Publication Date: 12/16/2004
Citation: Schrader, K., Dayan, F.E., Nanayakkara, D. 2004. Generation of reactive oxygen species by a novel anthraquinone derivative in the cyanobacterium planktothrix perornata (skuja). Journal of Pesticide Biochemistry and Physiology. 81:198-207. Interpretive Summary: The manner in which a natural-based compound kills a certain type of blue-green algae that is responsible for causing musty off-flavor in farm-raised channel catfish was investigated. The results from these tests determined that the natural-based compound produces certain types of products inside the cells of the musty blue-green algae that may kill them.
Technical Abstract: A water-soluble anthraquinone derivative (2-[methylamino-N-(1'-methylethyl)]-9,10-anthraquinone monophosphate), previously found to be selectively toxic towards Planktothrix perornata at very low concentrations (0.1-0.3 uM), was studied to determine its toxic mode of action towards this cyanobacterium. Chlorophyll fluorescence was monitored as an indicator of photosynthetic efficiency, and measurement of reactive oxygen species (ROS) was performed using the ROS-sensitive probe 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA). The effects of the herbicide paraquat (a ROS generator) and ascorbate (a ROS-scavenger) on ROS formation by P. perornata were also studied. Our results indicate that the water-soluble anthraquinone derivative does not inhibit photosynthetic electron transport directly, but does generate ROS at levels that may cause toxicity towards P. perornata